Abstract: (-)-Gossypol was isolated from cottonseed of species Gossypium barbadense L.. This is the first report of (-)-gossypol occurring in nature. It was found that there is a correlation between Gossypium species tested and optical activity of gossypol isolated. 1. Gossypol from cottonseed generally consists of unequal parts of enantiomers. In other words, gossypol from cottonseed contains (+)-gossypol and an excess of one enantiomer. 2. Gossypol occurring in cottonseed from the same species contains the same enantiomer in excess such as, the enantiomer in excess is (-)-gossypol in cottonseed of G. barbadense and is (+)-gossypol in cottonseed of G. hirsutum. It was shown by most varieties that gossypol in cottonseed of G. barbadense had optical purities varying from 10～25% and that of G. hirsutum varying from 10～20%.